Sewing machine



Feb 24, i948. J. H. PlKus'., j 2,43

SEWING- MACHINE Filed April 19, 1944 4 Sheets-sheet 1 Feb. 24, 48. .1.H. PIKUL.

SEWING MACHINE Filed April- -l9, 1.944 4 Sheets-Sheet 2 INVENTUR: cgw.

EIY

.5, H. PHKUL, I, 436,449

SEWING MACHINE Filed April 19, l944 4'Sheets-Sheet 3 INVENTUR 5mt@ se,CPM EN ATFYE r J. H. PlKUL SEWING MACHINE Feb. 24, 1948.

.Filed April 19, 1944 l4 Sheets-Sheet 4 ibn/ENTER:

Patented Feb. 24,l 1948 SEWING MACHINE Joseph H. Pikul, West Newton,

'. lhe Reece Corporation,

Mass., assignor to a corporation of Maine Application April 19,1944,Serial No. 531,706

11 claims. (ci. i12-242) This invention relates to sewing machines andmore particularly to the thread-handling mechanisms thereof.

It is an imperative requirement of any modern sewing machine that astitch is being formed with the first reciprocation of the needle in anoperating cycle of the machine.l To attain this end, it is customary toprovide a thread pull-off which draws extra thread from the threadsupply and makes it available to the needle for the formation of the rststitch, so that the thread end will remain in the work and not be pulledtherethrough by the action of the stitch-forming instrumentalities. Theconventional thread pulloifs, however, lack control over the extrathread and leave the same dangling on the machine for use by the needle,with the result that at least the first stitch is loose and irregular inappearance as compared with the subsequent stitches.

It is the primary aim and object of the present invention to provide ina sewing machine a thread pull-off which controls the extra thread drawnfrom a thread supply, to the end that the extra thread provided is at notime appreciably slackened and is made available to the needlesubstantially at the rate at which the latter requires it for theformation of the rst stitch.

The invention will best be understood from the following description ofan illustrative embodiment thereof shown in the accompanying drawings,in which Fig. 1 is a fragmentary side elevation, partly in section, of asewing machine embodying the present invention.

Fig. 2 is a fragmentary section, taken on the line 2 2 of Fig. 1.

Fig. 3 is an enlarged, fragmentary front elevation, partly in section,of the machine.

Fig. 4 is an enlarged, fragmentary section, taken on the line 4 4 ofFig. 1.

Figs. 5 and 6 are fragmentary side elevations, partly in section, of themachine, showing certain cooperating elements in different positions ofoperation. f

Figs. 7 to 10, inclusive, are fragmentary side elevations of the machinesimilar to Figs. 5 and 6, and showing contain cooperating elements indifferent positions of operation.

Fig. 1l is a front elevation of the looper mechanism employed inthe'present machine; and

Fig. 12 is'a front elevation of the same looper mechanism in a diierentoperating position.

While the invention is not limited in its appli- Y cation to anyparticular type of sewing machine, it is for convenience illustrated inconnection with a 'button sewing machine of the character shown anddescribed in U. S. Letters Patent No. 2,158,171, issued May 16, 1939.This machine has a base I5 supporting a work plate I6, and anoverhanging head I'I in which is suitably guided a needle bar I8,carrying a needle I9 which cooperates with underthread or loopermechanism 29, including loopers 2I and loop spreaders 2I a (Fig. 11), toat-l tach to work W supported on the work plate I6 a flat perforatedbutton B. held by a combined presser foot and clamp assembly C. Theconstruction of the combined presser foot and clamp assembly does notform a part of the present invention, and is for this reason notdescribed in detail herein.

The assembly C is carried by an arm 22 which extends'from a rod 23slidably secured, as by bearings 24, to the outside of the casing (Fig.3). The rod 23 carries a pin 25 engaged by a yoke 26, formed in one arm21 of a lever 28 which is mounted on a rock shaft 29, extending throughthe head head (Figs. 1 and 2). A torsion spring 30 normally urges theshaft in a counter-clockwise dil rection as viewed in Fig. 1 to maintainthe assem-V bly C in its lowermost or work clamping position.'` Theother arm 3I of the lever 28 is connected by suitable linkage 32 with atreadle 33. When the treadle 33 is depressed, the lever 28 and shaft 29'in Fig. 1, raising are rocked clockwise as viewed the rod 23 and theassembly C.

The looper mechanism 20 is mounted on a shaft `34, driven by suitablemeans (not shown) which' oscillates said looper mechanism in timedrelation with the needle reciprocations. The needle bar I 8 isreciprocated longitudinally by mechaf nism including a crank 35 (Fig.2), connected to the needle bar by a link 36. The crank 35 is secured toa needle shaft 3l, driven by means (not shown) which are, or may be,similar to those described in Patent No. 2,158,171.

In the present machine, the thread t passes from a needle thread supply(not shown) to the needle I 9 through a permanent thread tension 38 anda controlled thread clamp 40, as well as through a stitch-setting member45 on the head r of the machine and a thread tension 39 on the needlebar I8. The thread also passes over pins 4I and 4Ia onthe head I'I. Thetension 38 prevents an over-draft of the thread from the supply, landthe tension 39 is relatively light and serves to hold the threadv tautbetween itself and the needle eye. The thread clamp 40 is normallyclosed to prevent the passage of thread, but is held open during a .partof each work-penetrating I I and journalled in the walls of thestroke ofthe needle by a cam 42 (Fig. 3) which is carried by the needle crank 35.The cam 42 is adapted to depress a plunger 43 in the wall of the head I1against the tension of a spring 44 which normally holds the clamp 45closed. Such depression of the plunger 43 opens the clamp 40 and permitsthe needle to draw through it an amount of thread adequate for theformation of each stitch. The stitch-setting member 45 is provided atits free end with an eye 46 through which the thread passes, and lsadjustably secured by a screw 41 to one side of the head I? at a pointbe tween the needle-bar tension 39 and the clamp'40.

In accordance with the present invention, a curved arm 5d is securedtothe outer end of a rock shaft 5I which is journalledina bearing 52 inthe head of the machine. A slot or thread passage 53 is formed in alateral lug 5A of the arm 5B, and a member 55, having an eye or threadpassage 56, is adjustably secured to said arm 58 by means of a screw 58which extends through a slot 51 'in .the member .55 and is threaded insaid-arm 50. l

Mounted on the inner endof Vthe rockv shaft 5l is an arm yb5),Vcarr-yinguat its freey end a laterallyy projecting pin B0, normally"adapted to be received ina notch Si in a latch lever 52, pivoted at vE3to the wall of the head Hand urged in a clockwise direction as viewed inFig. 1 by a tension spring 154. A laterallyprojecting pin 55 on thelatchlever E2 isfadapted to be engaged by a radial finger -dlsecured ontherockshaft 29. A link B1 (Fig. 4) connects thefarm 59 with a lever 58,pivoted at 59 to the head Hof the machine and having intermediate itsends a cam. follower 1.!! adapted to cooperate-with a cam 'H on theneedle shaft .31. A suitably7 mounted torsion spring 'i2 (Figs. land 2)urges the arm..5 in a counter-clockwise direction as viewed in Fig. 1and, through intermediationof the arm 59 and link 67, urges the follower10. of the lever 68 against the cam 1I.

After the machinehas concluded a sewing operation, the operatordepressesthe tread-le 33 so as to lift the assembly C and permit theremoval ofthework. New work may then beiinserted in the machine, whereupon .theyassembly C is lowered byreleasing `the treadle 33. `.in-lifting theassembly C as -described, the finger 65 -on the rock shaft 29 engagesthe-.pin v6.5 on the latch lever 62 and swingsthelatter from theposition shown in Fig. 5-intoY that showninliig. 6,A thereby releasingthe pin-,5.9 on the arm ,59 and permitting the arm 5d to .swing fromtheV home position shown in Fig..5 into-theintermediate position shownin Fig. dwhilethelever `B8 is movedfrom the dot-and-dash line-positioninto .the full line position shown'in Fig-4,. i. e., into engagementwi-ththe cam li. The swing of the arm v5l! from home position into theintermediate Aposition (Fig. 6) is relativelyV short and insucentto pullextra thread -fromthe supply.

Themachine is nowready to be started, and the cam 1l will, on rotationin the direction ofthe arrow 'Ila (Fig. 4) and during the first descentof theneedle i9 from its uppermost position (Fig. 5) intothe'intermediateposition I9' (Fig. l), lowerfthe arm-50 from theintermedlate position shown in Fig. "6 into the lower'-most'position-shownin Fig; 1. ,Whilethe arm 53 is thus rlowered, thethread passage --53 in the latter will draw extra thread from the threadsupply through'thetension-33 and to one side of the closed clampA d8,whilethe thread passage 55 in the member 55 will belowered sogasV topermit a partial collapse of the thread between the closed clamp i0 andneedle bar tension 39. However, the memebr 55 is preferably so adjustedon the arm 5i] that the resulting slack in the thread between the clampM) and needle bar tension 39 is created not appreciably in excess of therate at which the descending needle will use up said slack withoutwithdrawing thread through the needle eye. During furtherdescent of theneedle it from the position I9 (Fig. Y1) into the position I9" (Fig. 9),the cam d2 opens the thread yclamp 4i? and the cam H retracts the arm 58.fromthe lowermost position shown in Fig. 1 into the intermediateposition shown in Fig. 9, whereby the. thread passage 53 in said arm 5Breleases :the extrathread. previously drawn from the supply to `theopenthread clamp 4B, and said released thread is drawn through said openclamp by the tension 39 and the force with which the thread isfrictionally retained on the needle when the same passes. through thework. -W. When the needle i9 reachestheposition l.9" in Fig. 9, the cam#i2 clears the plunger 43 of the thread clamp lidand the latter ispermittedto close, with the result that the thread between the clamp 49and the eye of the needle I9 is, during the last part of .the descent ofthe needle from the position i9 into the lowerrnost position l9" (seedot-anddash line position in Fig. 9), sufficiently tensioned to assurethat a threadloop Z is being cast bythe needle on its following ascent.When theneedle reaches its lowermost position, a substantial length ofthe threadend beyond the needle eye projects from one of the holes inthe button B, and most oithis projecting thread-lengthis subsequentlywithdrawn through said hole during the seizure and deflection of theloop l by one of the loopers andthe cooperating loop spreader of theloopermechanism 20 (Fig. 10) As the needle [Qascends from itslowermostposition into the uppermost position, the needle thread between theworkand the stitch-setting` member'4o is merely deected by the needlevbar tension 39 whose .threadclamping force 4is insuicient to draw thethread end through the work. Shortly before the needle reaches itsuppermost position, the cam 'H returns the arm 5!) from the intermediateposition shown in Fig. 10 into the home position shown. in Fig. 5,whereby the thread passage 56V in the member 55 slightly retracts theneedle thread through the eye pf the needle I9 tothe extent that thethread end is withdrawn below the top surface of-the button B butremains in the work W (Fig. l1). -Whenthe arm 5B- isreturned tohomepositiornthe latch lever 62 is permitted to return to iatchingposition (Fig. 5) and the arm 50 is latched in home or inactivepositionduring the remainder of the operating cycle of the machine,thoughy its actuating cam H turns with the needle shaft 37 throughouttherremainder of said operating cycle. More particularly, the arm 50 isreturned to home position when the crest c of the cam H (Fig. 4) isopposite the follower 10 on the lever @3. This cam. crest c isyimmediately foliowed by a cam descent d, the point e of which isopposite the follower 'it in the intermediate position of the cam 'll sothat said follower Ymay rise into engagement with the cam point e andpermit the arm 5S to move into theintermediate position shown in Fig. 6on being unlatched in home position when the operator raises the clampassembly C, as described. While the left hand looper 2l and spreadervzlahold the loop l deflected as shownin Fig. 11, the needle againfde'- Yscends, through the other hole in' the button B, however, and enters thedeflected loop l. After the needle I9 has entered the deflected loop land before it reaches its lowermost position, the looper mechanism 20 isrocked counterclockwise as viewed Yin Fig. 11 until the left hand looper2| and spreader 2Ia clear the loop l. Thereafter, continued downwardmovement of the needle I9 into its lowermost position will result inslight contraction of the loop l (Fig. 12) due to withdrawal of threadtherefrom by the needle, all the extra thread being used up and thethread between the clamp 40 and the needle being taut at this time.Thus, the loop l is suiiciently contracted to be out of the way of theright hand looper 2| and spreader 2| a when the same seize thev loop vZ.cast by the needle on its following ascent (Fig. 12). The stitch-settingmember 45 is so angularly adjusted on the machine head YIT that thethread between the work W and the clamp 40 is, during the last part ofthe ascent of the needle on each following reclprocation in theoperating cycle of the machine, suiciently deiiected by the needle bartension 39 to impose tension on said thread and thereby set each stitch.Also, after the needle I9 has entered the" deflected loop held by alooper and cooperating loop spreader and before the needle reaches itslowermost position on each following descent, the deected loop isreleased from its looper and spreader and the needle will then, oncontinued movement into Ylowermost position, withdraw suiiicient threadfrom the released loop to contract the latter out of the way of theother looper and spreader which will seize the next loop.

Since the arm 5U is adjustably mounted on the rock shaft 5I, preferablyby being clamped thereon as at I (Figs. l and 2) and the mem ber 55 isadjustable on the arm 5D as explained, the needle thread in the machinemay, for the successful formation of the first stitch in each operatingcycle, be regulated to suit most any conceivable sewing condition. Byproperly designing the cam 'II and properly adjusting the arm U andmember 55, the condition is readily attained where the normally guidedneedle thread between the thread clamp 40 and the needle bar tension 39is partly collapsed substantially at the rate at which the needle on itsrst descent uses up the resulting thread slack, and the extra needlethread drawn from the thread supply is released to the needlesubstantially at the rate required by the latter during its continueddescent, with the result that the thread in the machine is at no timeappreciably slackened and is always under the full control of thestitch-forming instrumentalities. Actual tests on a machine of this typehave shown that, on properly adjusting the arm 50 and member 55 andbyusing a cam 'Il of proper design, no thread is withdrawn through theeye of the needle during the first descent of the same, except anegligible length during the very last part of the needlejdescent afterthe clamp 40 is closed and the threadvtensioned to assure the casting ofa loopb'ythe needle on its following ascent. Thus, the thread was markedwith a pencil at the needle eye, and the pencil mark on the thread didnot shift relative to the needle eye in any of the needle positionsshown in Figs. 6 to 9, inclusivepwhile the thread in the machine was atthe same time observed to be substantially taut.

I claim: y

1. In a sewing machine, the combination with a reciprocatory needle andthree successive thread tensioning devices of which one endmost deviceis movable with the needle and the intermediate device is a thread clampoperable to grip and release the needle thread, of mechanism providing athread guide between a first pair of devices consisting of said endmost'and the in-` said clamp is open.

2. The combination in a sewing machine as set forth in claim 1, in whichsaid thread guide and pull-off are relatively adjustable.

3. In a sewing machine, the combination with an eye-pointed needle,means to reciprocate the same including a drive shaft, and successivethread tensioning devices` between said needle and a needle threadsupply of which an endmost device is movable with saidneedle, ofmechanism to guide the needle thread between said devices, saidmechanism being movable from a certain position to slacken the threadbetween two successive devices of which one is said endmost device andto draw extra'needle thread from the supply through another of lsaiddevices, and also movable into said certain position to cooperate withthe descending needle in drawing said extra thread between said twosuccessive devices, and a cam on said drive shaft for moving saidmechanism from and into said certain position while the needle descendssuch that the thread between said two successive devices remainssubstantially taut and the length of the thread end extending from theneedle eye remains :unchanged substantially throughout said needledescent.

4. In a sewing machine,^the combination with a needle, means toreciprocate the same including a drive shaft making one revolution foreach needle reciprocation, and successive thread tensioning devicesbetween said needle and a needle thread supply of which an endmostdevice is movable with said needle, of movable mechanism to guide theneedle thread between said devices, said mechanism being normally urgedfrom home position into another position to slacken the thread betweentwo successive devices of which one is said endmost device and to drawextra needle thread from the supply through another of said devices, andmovable back into home position to cooperate with the descending needlein drawing said extra thread between said two successive devices, areleasable latch arresting said mechanism in homeposition, and a cam onsaid drive shaft engagedby said mechanism. on slight movement of samefrom home position into an intermediate position, said cam being adaptedduring one revolution to control movement of said mechanism from saidintermediate position into said other position and then cause movementof said mechanism back into home position.

5. In a sewing machine, the combination with a work support, a liftablework clamp, a needle, means to reciprocate said needle including a driveshaft making one revolution for each needle reciprocation, andsuccessive thread tensioning devices between said needle and a needlethread supply of Whichauendmost deviceis ,movable with saidneedle,omovablefmechanism-to guide the needle. thread. between Ysaid devices,said mechanism .being normally urged from home position into anotherposition to :slacken the thread between two successive devicesiof-whichone is said endmost device and to :draw- -extra needle .thread from thesupply throughanother of. said devices, and movable back into :homeposition to draw said extra thread .betweensaid two devices, a movablelatch adapted, when Vin operative position, to arrest saidmechanism inhome position, a cam on. said .driveshait engaged by said mechanism onyslight movement fof same from home position into Van linter-mediateposition, said cam being adapted--duringionelrevolution to controlmovement of saidmechanism from: said intermediate position into saidother position vand then cause movement `of said mechanism back intohome position, andmeans to withdraw said latch from operative positiononliftingsaid work clamp and to return said latch intopperative positionon lowering said work clamp.

6. In a. sewing machine, :the combination'of -a reciprocating needle:ba-riga needle carried thereby, a releasable .normally `closed threadclamp disposed between the needle and athread supply, a reciprocatingtension operative to draw slack thread toward the work while the clampis closed, and a movable device ,between the thread clamp and needleoperative when the clamp is closed to give up thread .to thereciprocating tension as the needle moves toward the work.;I

'7. In a sewing machine,V .the combination with a reciprocatory.need-le, a thread tension movable withsaid needle .andza relea-sablethread clamp between a thread. supply arid .said tension, of ay devicenormally posltionedsto guide the thread from said clamp to saidtension,.said device being movable from itsnormalposition to slacken theguided thread so as :to supplyfpart of it to said tension whensaid-clamp iszclosed, and returnable to its normal position toscooperatewith the descending needle in .drawing thread through said clamp Whilethe latterxisreleased.

8. In a sewing machine, the combination with a reciprocatoryl needle, athread .tension movable with said needle and .afreleasable thread clampbetween a thread supply and said tension, -of a device normallypositioned to guide the thread between said tension and-threadsupply,said device beingmov-able ,from its normal position to drawyextra thread frcmsaidsupply, and simultaneously slacken the threadbetween said clamp and tension soias to supply part of it to saidtension, when said v,clamp is closed, and returnable to its .normalposition .tocooperate with the descending needle in drawing said extrathread through said clamp while the latter is released.

9. The combination in a sewing machine as set forth in claim 8, inwhichsaid device comprises a thread guide between saidV clamp and tension and.a thread pull-off between said clamp and thread supply.

10. In a sewing machine, the combination with stitch-forming mechanismincluding a reciprocatory, eye-pointed needle, a thread tension movablewith said needle, a releasaole thread clamp between a thread ,supply andsaid tension, and means for operating said mechanism through a sewingcycle, .of a device normallyv positioned to guide the thread betweensaid tension and thread supply and being movedrin timed relation withsaid operating means, .first from its normal position and while saidvcla-mp is. closed to draw extra thread from said supply .andsimultaneously slacken the thread between said clamp and tension so asto supply part of it to said tension when, and at the rate at which,said needle requires thread during .a part of its -rst descent in asewing cycle without withdrawing thread through the needle eye, .andthen back to its normal position tov cooperate with theneedle, still onits rst descent, in drawing said extra thread through said clamp whilethe latter is released.

1l. The combination in a .sewing machine as set forth in claim 10, inwhich said device draws extra thread of an amount to replenish thethread between said tension .and clamp onmovement of said device intoits normalposition, and to supply said .tension with .the threadrequired by the needle substantially for .the remaining part of its rstdescent .in a sewing cycle ywithout withdrawing thread through theneedle eye.

. JOSEPH H. PIKUL.

REFERENCES CITED The following references are of record in the file ofvthis patent:

UNITED 'STATES PATENTS Number Name Date 1,983,555 McCann Dec. 11, 19342,347,761 Bedard May 2, 1944

